Generally, the hydraulic brake system of a vehicle has potential drawbacks in that the hydraulic pipe is susceptible to damage, the response against transmission time of the hydraulic pressure is deteriorated, and the number of components required for the hydraulic pipe is increased.
In order to overcome the above drawbacks, an electric motor can be used to the brake system. However, since only a small electric motor can be mounted in the brake system, sufficient braking force may not be obtained in the brake system.